QUANTIFICATION OF OPTICAL ABSORPTION COEFFICIENTS USING ACOUSTIC SPECTRA IN PHOTOACOUSTIC TOMOGRAPHY

摘要

Accurately quantifying optical absorption coefficient using acoustic spectra of photoacoustic signals. Optical absorption is closely associated with many physiological parameters, such as the concentration and oxygen saturation of hemoglobin, and it can be used to quantify the concentrations of non-fluorescent molecules. A sample is illuminated by, for example, a pulsed laser and following the absorption of optical energy, a photoacoustic pressure is generated via thermo-elastic expansion. The acoustic waves then propagate and are detected by a transducer. The optical absorption coefficient of the sample is quantified from spectra of the measured photoacoustic signals. Factors, such as system bandwidth and acoustic attenuation, may affect the quantification but are canceled by dividing the acoustic spectra measured at multiple optical wavelengths.

主权项

1. A method of quantifying an optical absorption coefficient of an object, said method comprising:
directing a first light pulse emitted by a light source into a volume of the object, wherein the first light pulse has a first wavelength; receiving at an acoustic transducer a first acoustic wave emitted by the object in response to receiving the first light pulse; performing on a controller a Fourier transformation on the received first acoustic wave to generate a first acoustic spectrum; directing a second light pulse emitted by the light source into the volume of the object, wherein the second light pulse has a second wavelength; receiving at the acoustic transducer a second acoustic wave emitted by the object in response to receiving the second light pulse; performing on the controller a Fourier transformation on the received second acoustic wave to generate a second acoustic spectrum; and quantifying the absorption coefficient of the volume of the object, wherein the absorption coefficient is a function of the first acoustic spectrum and the second acoustic spectrum.